From German Patent No. 100 57 258, a method for side crash detection using a temperature sensor is known; this sensor measures an adiabatic increase in temperature upon a deformation of a side part of a vehicle. The absolute temperature increase and the temperature gradient are ascertained. They are compared with predetermined thresholds, to ascertain whether a side crash is involved, or not. Only if both thresholds are exceeded does a side crash exist, and a plausibility check is performed with an acceleration sensor. As a function of the plausibility check and the collision signal, restraint means are deployed as appropriate.
From European Published Patent Application No. 667 822, a pressure sensor is known which detects an adiabatic pressure increase in a largely closed side part of the vehicle body as a collision evaluation parameter. Once again a plausibility sensor is provided. Filtering of the signal below one kilohertz may be provided.
From German Patent No. 198 30 835, a method for deploying a restraint means is known in which a sensor system furnishes a pressure signal. The algorithm that detects the collision uses a variable threshold, which depends on the change in the pressure signal.
From German Patent No. 196 19 468, a method for deploying a restraint means for side crash protection in a vehicle is known in which the deployment of a restraint means is performed as a function of a mean value signal of the pressure signal and as a function of an increase in the pressure signal.
A disadvantage of the algorithms proposed in the related art for evaluating pressure and temperature signals is that there are some instances that do not call for deployment that are difficult to distinguish from genuine crashes. Especially the impact of a soccer ball, kicks, or a bicycle, or at least shutting doors very forcefully, generates pressure and temperature signals that in general are hard to distinguish from crashing into a pole at low speed.